Operators are beginning to roll out circuit-packet, inter-technology networks where a circuit RAN (radio access network) delivers circuit services support and a packet data RAN delivers packet data services support to a user via ‘dual mode’ mobile station device or a hybrid mobile capable of communicating with both a circuit RAN and a packet data RAN via two access network technologies.
Circuit services support typically includes traditional circuit voice service, Short Message Service (SMS), etc., while packet data services include support for internet applications such as VoIP (Voice over IP), Video Telephony, Instant Messaging, email, etc.
A circuit RAN may include for example a cdma2000 1x RAN as specified by the 3GPP2 A.S00011-CS0008-A and A.S0009-A, and/or some other IEEE 802.x-based packet data network (802.16, e.g.).
FIG. 1 is a block diagram depiction of a wireless communication system 100 in accordance with the prior art. FIG. 1 depicts a circuit-packet, inter-technology network in which the circuit RAN provides circuit voice services support and a packet data RAN such as an HRPD, WiMAX, or other IEEE 802.x-based packet data network provides packet data services to a user of a dual technology mobile. It is assumed here that the circuit network does not support packet data services.
FIGS. 2 and 7 are respective block diagram depictions of 3GPP2 A.S0008-B and A.S0009-B inter-technology networks 200 and 700 in which the circuit RAN provides circuit voice service support and an HRPD RAN provides packet data services to a user of a dual mode mobile. The IWS Function, as specified in A.S0008-B, for example, may be collocated at either the 1x BS or at the HRPD AN, or may exist as a standalone entity. When the IWS function is collocated at the 1x BS, an A21 interface terminates at the 1x BS and the HRPD AN. When the IWS function is collocated at the HRPD AN, an A1/A1p interface is supported by the HRPD RAN and terminates at the MSC and the HRPD AN, and the A21 interface is internal to the HRPD AN. When the IWS exists as a standalone entity, an A1/A1p and A21 interface is supported by the HRPD RAN. The A1/A1p interface terminates at the MSC and the IWS, and the A21 interface terminates at the IWS and the HRPD AN.
In these types of circuit-packet, inter-technology networks, a dual mode mobile currently active with a call is typically ‘cross-paged’ by the corresponding inter-connected serving RAN, since dual mode mobiles may only be able to monitor incoming signaling from a single air interface at a time. Messages between the circuit RAN and the packet data RAN are exchanged over an inter-technology signaling interface (e.g., an A21 connection). For example, messages originating from the circuit network are sent by a circuit node in the circuit RAN over the inter-technology interface to a packet data node which is providing packet data services to the mobile in the packet data RAN. U.S. patent application Ser. No. 11/141,926, entitled “METHOD AND APPARATUS TO FACILITATE INTER-OPERABILITY BETWEEN A 3G1X NETWORK AND A WIRELESS PACKET DATA NETWORK,” may be referenced for examples of how a packet RAN may be notified of an incoming circuit voice call from a 1x circuit network.
In order for multiple networks to effectively and efficiently serve a multi-mode mobile, the mobility of the mobile must be adequately supported by the networks involved in providing service. In other words, the network nodes from each overlaid network must adequately keep track of the mobile as it moves from one service area to the next within such a system. If the mobility of the mobile is not adequately supported, functionality such as cross-paging will not operate effectively and efficiently as the mobile moves throughout the system. Accordingly, it would be highly desirable to have a method and apparatus for supporting mobility in an inter-technology network.
Specific embodiments of the present invention are disclosed below with reference to FIGS. 3-6. Both the description and the illustrations have been drafted with the intent to enhance understanding. For example, the dimensions of some of the figure elements may be exaggerated relative to other elements, and well-known elements that are beneficial or even necessary to a commercially successful implementation may not be depicted so that a less obstructed and a more clear presentation of embodiments may be achieved. In addition, although the signaling flow diagrams above are described and shown with reference to specific signaling exchanged in a specific order, some of the signaling may be omitted or some of the signaling may be combined, sub-divided, or reordered without departing from the scope of the claims. Thus, unless specifically indicated, the order and grouping of the signaling depicted is not a limitation of other embodiments that may lie within the scope of the claims
Simplicity and clarity in both illustration and description are sought to effectively enable a person of skill in the art to make, use, and best practice the present invention in view of what is already known in the art. One of skill in the art will appreciate that various modifications and changes may be made to the specific embodiments described below without departing from the spirit and scope of the present invention. Thus, the specification and drawings are to be regarded as illustrative and exemplary rather than restrictive or all-encompassing, and all such modifications to the specific embodiments described below are intended to be included within the scope of the present invention.